Acetylene-gas generator



July 2, 1929. c. w. BECK ACETYLENE GAS GENERATOR I Filed Jan. 23, 1922 3Sheets-Sheet 2 July 2, 1929. c. w. BECK 1.719.162

ACETYLENE GAS GENERATOR Filed Jan. 23, 1922 3 Sheets-Sheet 3 PatentedJuly 2, 1929.

PATENT OFFICE.

CHARLES W. BECK, F DETROIT, MICHIGAN.

AGETYLENE-GAS GENERATOR.

Application filed January 23, 1922. Serial No. 531,217.

This invention relates to improvements in acetylene gas generators.

lt is the practice in machines of this kind to deliver the carbide, inintermittent charges to the water in the tank, and permit the same topass to the bottom of the tank into the sludge. This method is highly obect1onable because in operating in this way, experlence has shown thatunspent portions of the charge accumulate in the sludge and often timeshas resulted in excess pressures and serious explosions. It is theobject of the present invention to increase the safety of suchapparatus; to provide for holding each charge of carbide in suspensionin the body of water free from the residue of previous charges, until itis fully spent, the dangerous accumulation of carbide in the sludge inthe bottom of the tank, before referred to, being thus avoided and theefficiency of the apparatus materially increased.

An important novel characteristic of the invention also resides in thespecific carbide feeding means provided whereby increased efficiency inthe feeding of the material is obtained and agas tight seal is providedbetween the tank and feed opening of the carbide chamber.

The invention, with other objects and advantages thereof, and thepart1cular construction, combinations and arrangements of partscomprising the same, will be understood from the following detaileddescription, when considered in connection with the accompanyingdrawings, forming part here of, and illustrating embodiments of theinvention. 1

in the drawings.

Figure 1 is a vertical section of an apparatus constructed in accordancewith the present invention.

Fig. 2 is a detail longitudinal section through the feed tube andscrcw.

Fig. 3 is a detail transverse section through the feed tube and screw.

Figure l is a side elevation with parts shown in dotted lines.

Figure 5 is a top plan view with parts shown in dotted lines.

Fig. 6 is a detail view on an enlarged scale, of part of the feedingmechanism.

Fig. 7 is a detail view of the spring retaining means associated withthe brake lever.

Fig. 8 is a detail view of the lost motion 1connection of the operatingrod and the brake ever.

Fig. 9 is an end elevation, on an enlarged scale, of the shaftpositioning means.

Fig. 10 1s a vertical section of a modified construction.

Fig. 11 is a detail longitudinal section, on

an enlarged scale, through the feed tube and screw illustrated in Figure10.. The invention eomprehends carbide feedng means controlled by thegas pressure, and 1n combination therewith a screen, perforated shelf ortray arranged in the tank to receive the'carbide from the feeding meansand to hold the same in a layer in suspension in the body of water nearthe surface thereof, said screen, perforated shelf or tray, beingadapted to be shifted to dump any foreign matter from the spent chargeand to present a fresh surface free from the residue of other spentcharges, to-receive the following charge, pro- 'VlSlOll being thus madewhereby each charge of carbide is held suspended in the body of waternear the surface thereof. 7

While specific embodiments of the invention are illustrated in thedrawings, it will of course be understood that changes and variations inthe particular constructions shown, and the carrying out of theinvention in other forms, as will appeal to those skilled in the art andfalling within the scope of the appended claims may be practiced withoutdeparting from the spirit of the invention.

Referring to a detail description of the drawings, 1 designates aconventional form of tank, having a water supply pipe 1. 2 designatesthe carbide chamber or receptacle at the top of the tank 1 having ahopper bottom 3 with an outlet part 4 and feed tube 5, the latter havingan outlet opening 6 leading into the tank 1. The outlet part 4 hasoffset or angularly disposed portions 4*, 4", and within the receptacle2 over the outlet portion 4 is a cylindrical partition 7, theseconstructions being adapted to prevent packing or wedging of thematerial above and within the outlet part 4:. 9 and 10 are gas outletpipes, the pipe 9 leading from the upper part of the tank to the upperportion of the carbide chamber 2, and the pipe 10 leading therefrom i tothe usual gas hell, (not shown) or directl v to the service line. 11designates a filling opening, and 11' is a removable screw plug or covertherefor.

' provide a. gas tight packingor seal between the tank 1 and the feedopening 4 of the carbide chamber'. 13 designates the shaft of the feedscrew su ported in bearings 14, and 15 on the feed tube. In thearticular construction shown, the main rigid portion 17 of the blade ofthe feed screw is providedsvith a recess 18 at one side thereof, andseatedin the recess and projecting beyond the periphery of the mainrigid blade portion is a strip of flexible material 19. The strip 19 maybe formed of soft rubber, leather or any other material suitable for thepurpose, soft rubber being preferred. The strip 19 is supported andtightly held in place within the recess against the side wall thereof bya clamping stri 20 ofmetal or other suitable material, sai strip 20,which is conveniently formed in sections, as shown, being secured to themam rigid portion 17 of the feed screw by screws or e uivalent fasteningmeans 21. In order to a ditionally guard against the escape of moist gasfrom the tank 1 into the discharge opening 4 of the carbide chamberthrough the feed tube 5, said tube is provided with a valve 5', saidvalve being in the form of a plate hinged at its upper portion to anupper part of the tube, as shown, the valve being yieldablymaintained inclosed position against the end of the tube by gravity or other means.

Referring particularly to the construction illustrated Figures 1 to 6,of the drawings, the feed screw is; driven by a spring motor 24 mountedon the carbide chamber 2. The motor 24'whieh may be of any convenientconstruction is operatively connected with the feed screw through themedium of a vertical shaft 25 having pinions 26, 27 at opposite endsmeshing respectively with a pinion 28 on the feed screw shaft 12, and apinion 29 on the drive shaft 30 of the motor. Pressure operated meansfor controlling the operation of the motor is provided. 31 designates abrake disk on a shaft 32 connected by gears 33 with the driving shaft ofthe motor, and 34 is a brake lever provided with a shoe 34' to cooperatewith the brake disk 31.

The brake lever 34, which is pivoted at one end at 35, is connected by arod 36 with a diaphragm 37 arranged in the top of the tank 1 to beactuated by the pressure of the gas. At the outer side of the diaphragm37 is a coiled spring 38 arranged to exert pressure inwardly on thediaphragm, the force of the spring 38 beingssuch as to hold thediaphragm against outward movement until the pressure of the gas in thetank reaches a predetermined degree. The spring 38 is arranged within anexteriorly threaded tubular nut 39 which adjustably engages a threadedbushing 40 on the cap 41 that extends over the diaphragm 37, saidtubular nut being provided with an opening 39 in its top, through whichthe rod 36 extends, the rod 36 slidably engaging the walls of theopening which form a support and guide for the rod. As will beunderstood by turning the tubular nut 39 the tension of the spring 38can be adjusted. When the diaphragm is raised or elevated by the gas.pressure, the brake lever 34 will be raised to carry its shoe 34, intocontact with the brake disk 31 as indicated in Figure 4 of the drawings,and the motor will be held locked against operation until the pressurein the tank becomes reduced, the diaphragm being then forced downwardlyby the coiled spring 38 carrying with it the rod 36, the brake shoe 34being moved out of engagement with the brake disk 31, and the motorpermitted to operate to drive the screw to feed carbide from the carbidereceptacle to the tank.

The means for receiving the carbide from the feed tube 5 and for holdingthe same in suspension in the body of water in the tank, comprises ascreen, perforated shelf or receptacle supported for rotation in theupper part of the tank, said shelf or receptacle having two compartmentsdisposed diametrically opposite to each other with relation to its axisof rotation, the shelf or receptacle being adapted to be turned to dumpthe residue therefrom, and the arrangement being such that when one sidethereof or one of the compartments of the receptacle is inverted to dumpthe same, the other side or compartment is brought to horizontalposition just below the level of the. water in a position to receive afresh charge from the carbide receptacle. The perforated shelf or trayis shown as consisting of a single bottom wall or portion 41 with sidewall portions 4-2, 43, extending from each side of the bottom wall 41,providing oppositely disposed compartments. The perforated shelf orreceptacle is shown supported for rotation by shaft sections 44, 45extending from opposite ends of its bottom wall or portion 41", andengaging bearings 46, 47, on the wall of the tank.

The operating means for the carbide supporting tray or receptacle, inthis particular instance, is shown as comprising an extension 36' of therod 36, provided at its lower end with a spring pressed rack or pawl 49and a ratchet wheel 50 fixed on the shaft section 45, the arrangementbeing such that upon nection is provided between the upper end of therod 36 and the brake lever 34. In the particular constructionillustrated in the drawin the rod is provided with an elongated s 0t 36.For purposes of adjustment the rod is also shown provided with a screw36". 51 designates a spring which serves to maintain the brake lever 34in its uppermost position until moved downwardly by the rod 34 duringthe latter part of the downward movement thereof, said spring 51 beingsecured at one end to the motor casing and having its opposite endbearing laterally against one side of the brake lever, as shown, (seeFigure 7).

For the purpose of lnsurlng the proper p0: sitioning of the tray uponeach operation of the same by the pawl and ratchet mechanism,

the shaft portion 45 is provided with a squared part 45. 53 designates aring or yoke having a flat face 53? adapted to cooperate with the flatfaces of the squared portion of the shaft, a weight 54 being connectedwith the ring or yoke 53 and acting to yieldingly maintain the flatsurface of the ring or yoke flat against one of the flat faces of thesquared portion of the shaft.

55, designates a handle part connected wlth the shaft portion 45 andarranged outside of the tank whereby the tray may be operated manually.On the handle portion 55 is an indicator projection 55, which lies atthe upper part of the handle when the tray 13 m horizontal position.

The operation is as follows:

When the carbide feeding is in progress and while the gas is beinggenerated, the tray or shelf, is stationary and remains stationaryduring the expansion of the diaphragm.

After the gas has passed out through the service pipe and the diaphragmstarts to collapse or upon its inward movement the shelf or tray isturned to dump and reverse the same by the pawl and ratchet mechanism.the brake lever being actuated to release the motor upon the downwardmovement of the rod 36, after the tray or receptacle has been dumped andmoved to reverse position to receive a fresh charge of carbide upon itsreverse side.

It will be noted that the rotation of the screen or perforated traythrough the bodyof water assists in completely freeing it of any sludgeat each dumping operation. By generating the gas near the surface of thebody of water the time taken for the gas to pass upward and out of thewater is shortened,

thereby permitting the generator to be operated at lower pressures.

Also, at times, in the operation of acetylene gas generators in whichcarbide is fed into a body of water, the water supply becomes reduccd orscant and then the carbide is held in suspension near the top of thewater. Under this condition, when the sludge or lime thickens the water,the carbide accumulates on the surface of the body of water, until itbecomes too heavy a mass when it suddenly sinks and thereby generates adangerous abnormal pressure. This condition is entirely obviated inapplicants apparatus, the automatic shelf or screen, after each chargesubmcrges, serving to agitate and dump the residue of the charge.

In Figures 10 and 11' of the drawings, is illustrated a modified form offeed screw and operating mechanism. In these figures 56 is the tank and57 the carbide chamber provided with a discharge part 57 leading to thefeed tube 58. The feed screw, here shown, comprises a-shaft 59 providedwith an integral spiral metal rib. and an outer yieldable spiral'bladepart 60 adapted to tightly fit against the wall of the feed tube, saidyieldable part 60 being of rubber andformed by molding or casting thesame on the shaft. In this particular instance, the screw is mounted toreciprocate in the feed tube, the screw acting to free the carbidetherefrom on the for- Ward movement thereof. The operating means for'thescrew is shown as consisting of a diaphragm 61 connected with the screwby a rod 62, a spring 63 at the outer side of the diaphragm acting toexert pressure inwardly on the diaphragm, the tension of the spring 63being such as to hold the diaphragm inwardly until the pressure of thegas in the tank reaches a predetermined degree. The rod 62 is providedwith a universal joint 62. The joint 62' is arranged to cooperate withthe rear end of the feed tube to serve as means for limiting the extentof inward movemei t of the rod 62, the construction being such that whenthe screw has been moved to its outward limit. the rear end of the feedscrew lies ingvzardly of the opening of the discharge part What I claimis:

' 1. In a gas generator, a tank, means for supplying water to the tank,means for feeding carbide to the tank controlled by the gas pressure, incombination with a perforated shelf in the tank to receive the carbidefrom the feeding means, said shelf being adapted to be shifted to dumpthe spent charge therefrom, and mechanism governed by the gas pressurefor operating the shelf.

2. In a gas generator, a tank, means for supplying water to the tank,means for feeding carbide to the tank controlled by the gas pressure, incombination with a perforated shelf in the tank to receive the carbidefrom the feeding means, said shelf being adapted to be shifted to dumpthe spent charge therefrom, and mechanism operatively connected with thecarbide feeding means for operating the shelf prior tothe operation ofsaid feeding means.

- 3. In a gas generator, a tank, means for supplying water to the tank,means for feeding carbide to the tank controlled by the gas pressure, incombination with a perforated arranged and movably mounted within thetank whereby the same is adapted to be moved to dump the spent ehar efrom the compartments, and when one of the compartments is in dumpingposition, another of the compartments will be in receiving position, and

automatic means for shifting the receptacle d at intervals prior to theoperation of the feeding means.

5. In a gas generator, a tank, means for supplying water to the tank,means for feeding carbide to the tank controlled by the gas pressure, incombination with a perforated shelf in the tank to receive the carbidefrom the feeding means, said shelf being supported for rotation andadapted to be turned to reverse the same to dump the spent charge fromone side thereof and present its opposite side to receive carbide, andmeans acting automatically to shift the perforated shelf at intervalsprior to the operation of the feeding means;

6. In a gas generator, a tank, means for supplying water to the tank,means for feedingcarbide to the tank controlled by the gas pressure, incombination with a perforated receptacle within the tank to receivecarbide froin the feeding means, said receptacle being supported forrotation and comprising two per orated compartments arrangeddiametrically opposite each other, the receptacle being adapted to beturned to dump the spent charge from its compartments, and when one ofthe compartments of the receptacle is in dumping position the other isin receiving position, and automatic means for shifting the receptacleat intervals prior to the operation of the feeding means.

7. In agas generator, a tank, means for supplyingwater to the tank,means for feeding carbide to the tank controlled by the gas pressure, incombination with a perforated receptacle within the tank to receivecarbide from the feeding mechanism, said receptacle being supported forrotation within the tank and comprising a single bottom part with sidewalls extending from opposite sides thereof providing oppositely'disposed compartments, the receptacle being supported for rotation andbeing adapted to be turned to dump the spent charge from one of itscompartments and present the other in carbide receiving position, andautomatic means for shifting the receptacle at intervals prior to the oeration of the feeding means.

11 a gas generator, a tank, means for supplying water to the tank, meansfor feeding carbide to the tank, in combination with a perforatedreceptacle within the tank to receive carbide from the feeding means,said receptacle comprising a single bottom part and-side walls extendingfrom opposite sides of the bottom providing oppositely disposedcompartments, and journals extending from opposite ends of the bottompart engaging bearings on the tank and providing a rotatable support forthe receptacle, and automatic means for turning the receptacle'atintervals.

mgcarbidc to the tank including a feeding cv ce, power means for drivingsaid feeding device, and gas pressure controlling means for said powermeansincluding a diaphragm subject to the gas pressure in the tank, abrake for said power means, and an operative connection between thediaphragm and brake, in combination with a erforated shelf in the tankto-receive the car ide from the feeding means, said shelf beingsupported for rotation and adapted to be turned to dump the spentcharge, and an operative connection between the diaphragm and said shelffor rotating the shelf to dump the spent charge prior to the operationof the carbide feeding means. 10. In a gas generator, a tank, means forsupplying water to the tank, means for feeddevice, ;power meansfordriving the feeding means and pressure controlled regulating means forsaid power means including a diaphragm subject to the gas pressure inthe tank, a brake for said power means, a rod connected to the diaphragmand' with the brake, in combination with a perforated shelf within thetank to receive the carbide from the feeding means, said shelf beingsupported for rotation and adapted to be turned to dump the spent chargemeans, and a pawl and ratchet connection between said rod and shelf forturning the shelf to dump and reverse the same prior to the operation ofthe feeding means.

11. In a gas generator, a tank, means for supplying water to the tank,means for feeding carbide to the tank controlled by the gas pressure, incombination with a perforated shelf in the tank to receive the carbidefrom the feeding means, said shelf being supported for rotation.andadapted to be turned and reversed, and means for turning the shelfto reverse the same prior to the operation of the feeding means, saidmeans including a diaphragm subject to the gas pressure in the tank, anda pawl and ratchet connection between the diaphragm and the shelf.

'12. In a gas generator, a tank, means for supplying water to the tank,means for feeding carbide to the tank controlled by the gas pressure, incombination with a horizontally disposed rotary shaft in the tanksupported for rotation, a perforated shelf fixed on the shaft to receivecarbide from the feeding means, said shelf being adapted to be turnedand reversed by the rotation of said shaft, and operating means for theshelf including a diaphragm subject to the gas pressure in the tank, arod connected with the diaphragm, and a pawl and ratchet connectionbetween the rod and shaft.

13. In a gas generator, a carbide chamber, and feeding mechanismincluding a feed tube connected with said chamber, and a feed screwarranged to work in the tube, the main portion of the blade of the screwbeing formed of rigid material and provided with a recess at itsperiphery, and a strip of flexible material seated in the recess andpro'ecting beyond the rigid part of the blade to ear against the wall ofthe tube.

14. In a gas generator, a carbide chamber, a feeding mechanism includinga feed tube connected with said chamber, and a feed screw arranged towork in the tube, the main portion of the blade of the screw beingformed of rigid material and provided with a recess at one side thereof,a strip of flexible material seated in said recess and projecting beyondthe rigid part of the blade to bear against the wall of the tube, anouter clamping strip, and screws securing the clamping strip to therigid portion of the blade against one side of the flexible strip.

15. In a gas generator, a carbide cham-' her, and feeding mechanismincluding a feed tube connected with said chamber, and a feed screwarranged to work in the tube, the main portion of the blade of the screwbeing formed of rigid material and provided with a recess at its outerperiphery extending around one side thereof, a strip of flexiblematerial arranged in the recess with its outer portion projecting beyondthe rigid portion of the blade to bear against the wall of the tube, afastening strip, and screws for securing the fastening strip to therigld portion of the blade against one side face of the flexible strip,said recess being of a width so that the outer side face of thefastening strip extends substantially flush with the adjoinlng side faceof the blade.

16. In a gas generator, a tank, means for supplying water to the tank,means for feeding carbide to the tank controlled by the gas pressure, incombination with a perforate shelf in the tank to receive the carbidefrom the feeding means, said shelf being adapted to be shifted to dumpthe spent charge there from, an automatic mechanism for operating theshelf at intervals after the charge of carbide has given up its gas.

17 In a gas generator, a tank, means for supplying water to the tank,means for feedmg carbide to the tank controlled by the gas pressure, incombination with a perforated shelf in the tank to receive the carbidefrom the feeding means, said shelf being support ed for rotation andadapted to be turned to reverse the same to dump the spent charge fromone side thereof and resent its 0 pcsite side to receive a freshc argeof car ide, and means acting automatically to shift the perforated shelfat intervals after the charge of carbide has given up its gas.

18. In a gas generator, a tank, means for supplying water to the tank,means for feeding carbide to the tank controlled by the gas pressure, ahorizontally disposed shaft supported for rotation in the tank, aperforated shelf fixed on the shaft to receive carbide from the feedmgmeans, said shelf being adapted to be turned and reversed by therotation of said shaft, and operating means for the shelf including adiaphragm subject to the gas pressure in the tank, a rod connected withthe diaphragm, a pawl and ratchet connec tion between the rod and shaftproviding for rotation of the shaft upon movement of said rod in onedirection, in combination with positionlng meansassociated with theshaft ineluding a part on said shaft having angu larly related faces, amember associated with the shaft portion and having a fiat face portionadapted to engage the angularly related faces thereof, and meansyielolably holding said member with its flat face against one of theflat faces of the shaft.

19. In a gas generator, a tank, means for supplying water to the tank,means for feeding carbide to the. tank controlled by the gas pressure, ahorizontally disposed shaft supported for rotation in the tank, aperforated shelf fixed on the shaft to receive carbide from the feedingmeans, said shelf being adapted to be turned and reversed by therotation of said shaft, and operating means for the shelf including adiaphragm subject to the gas pressure in the tank, a rod connected withthe diaphragm, a pawl and ratchet connection between the rod and shaftproviding for rotation of the shaft upon movement of said rod in onedirection, in combination with shaft positioning means including asquared part on said chamber, a yoke associated with said squaredportion of the shaft and having an inner flat portion adapted to engageone of the fiat faces of the shaft portion, and a weight connected withthe yoke and acting to yieldably maintain the yoke in position with itsfiat face against one ofthe fiat faces of the shaft.

llEi

20. In a gas generator, a tank, means for supplying water to the tank,means for feeding carbide to the tank controlled by the gas pressure, incombination with a perforated shelf in the tank to receive the carbidefrom the feeding means, said shelf being supported for rotation andadapted to be turned to reverse the same to dump a spent charge from oneSide thereof and to present its opposite side to receive a fresh chargeof carbide, automatic means for operating the shelf at intervals, andmanually operable means to operate the shelf independently of saidautomatic means.

21. In a gas generator, a tank means for supplying water to the tank,and means for feeding carbide to the tank including a carbide chamberabove the tank having an outlet opening, a feed tube connected with theoutlet openin of the carbide chamber, the wall of the feed tube beingimperforate, a feed screw arranged to work in said tube, said screwhaving a flexible outer peripheral portion to bear against the wall ofthe feed tube and form a moisture tight seal between the tank and theoutlet opening of the carbide chamber.

22. In a gas generator, a tank, means for supplying water to the tank,means for feeding carbide to the tank including a carbide chamber abovethe tank having an outlet opening, a feed tube connected with the outletopening of the carbide chamber, the wall of the feed tube beingimperforate, a feed screw arranged to work in said feed tube, said feedscrew having a yieldable outer peripheral portion to bear against theWall of the feed tube and form a moisture tight seal between the tankand the outlet opening of the carbide chamber.

23. In a gas generator, a tank, means for supplying water to the tank,means for feed-, ing carbide to the tank including a carbide chamberabove the tank having an outlet opening, a feed tube connected with theoutlet opening of the carbide chamber, the wall "of the feed tube beingimperforate, a feed screw arranged to work in said feed tube, said feedscrew having an outer eripheral portion of rubber to bear against t ewall of the feed tube and form a moisture tight'seal between the tankand the outlet opening of the carbide chamber.

24. In a gas generator, a tank, means for supplying water to the tank,means for feeding carbide to the tank including a carbide chamber abovethe tank having an outlet opening, a feed tube connected with the outletopening of the carbide chamber, the wall of the feed tube beingimperforate, a feed screw arranged to work in said feed-tube said feedscrew having a flexible outer peripheral portion to bear against thewall of the feed moisture ti ht seal between the tank and the outletopening of the carbide chamber, said outer peripheral portion at itsmarginal edge having a beveled face.

25. In a gas generator, a tank, means for supplying water to the tank,means for feeding carbide to the tank including a carbide chamber abovethe tank having an outlet opening, a feed tube connected with the outletopening of the carbide chamber, the wall of the feed tubebeingimperforatc, a feed screw arranged to work in said feed tube, said feedscrew having a flexible outer peripheral portion to bear against thewall of the feed tube and form a moisture tight seal between the tankand the outlet opening of the carbide chamber, said outer peripheralportion at its marginal edge having beveled faces at opposite sidesthereof.

26. In a gas generator, a tank, means for supplying water to the tank,means for feeding carbide to the tank including a carbide chamber abovethe tank having an outlet opening, a feed tube connected with the outletopening of the carbide chamber, the wall of the feed tube beinimperforate, a feed screw arranged to wor in said feed tube, the mainportion of the blade of the feed screw being formed of ri id material,and yieldable means at the peripheral portion of the blade of the feedscrew to bear against the wall of the feed tube and form a moisturetight seal between the tank and the outlet opening of the carbidechamber.

In a gas generator, a tank, means for supplying water to the tank, meansfor feeding carbide to the tank including a carbide chamber above thetank having an outlet opening, a feed tube connected with the outletopening of the carbide chamber, the wall of the feed tube beingimperforate, a feed screw arranged to work in said feed tube, the mainportion of the blade of the feed screw being formed of rigid material,and a strip of flexible material secured to the outer peripheral portionof the rigid part of the screw and projecting beyond the same to bearagainst the wall of the feed tube and form a moisture tight seal betwenthe tank and the outlet opening of the carbide chamber.

28. In a gas generator, a tank, means for supplying Water to the tank,means for feeding carbide to the tank including a carbide chamber abovethe tank having an outlet opening, a feed tube connected with the outletopeningof the carbide chamber, the wall of the feed tube beingimperforate, a feed screw arranged to work in said feed tube, the mainortion of the blade of the feed screw being ormed of rigid material, anda strip of yield able material secured to the outer eripheral portion ofthe rigid part of the eed screw and projecting beyond the same againstthe wall moisture tight seal between the tank and the outlet opening ofthe carbide chamber.

29. In a gas generator, a tank, means for supplying water to the tank,means for feeding carbide to the tank including a carbide chamber abovethe tank having an outlet opening, a feed tube connected with the outletopening of the carbide chamber, the Wall of the feed tube beingimperforate, a feed screw arranged to Work in said feed tube, the mainportion of the blade of the feed screw being formed of rigid material,and a strip of rubber secured to the outer portion of the main rigidpart of the feed screw and projecting beyond the same to bear againstthe wall of the feed tube and form a moisture tight seal between thetank End the outlet opening of the carbide cham- 30. lln a gasgenerator, a tank, means for supplying water to the tank, means forfeeding carbide to the tank including a carbide chamber having slopingbottom walls, an outlet opening, a delivery spout leading from saidoutlet opening, a feed tube disposed at the lower end of andcommunicating with the delivery spout, and a feed screw in the feedtube, said delivery spout comprising oppositely inclined sectionsadjoining and disposed one above the other directly adjoining the feedtube, said delivery spout sections being of relatively small crosssectional size, and operating means for said feed screw.

In testimony whereof I hereunto afiix my signature.

CHARLES W. BECK.

